1. Field of the Invention
The instant invention relates to wrench adapters and in particular to an oil drain plug wrench adapter which allows a standard socket wrench to be used to remove and replace a two post oil drain plug.
2. Background of the Invention
Many small internal combustion engines such as those used to power lawnmowers, chainsaws, etc., use an oil drain plug design which incorporates a pair of upstanding posts. In order to drain the oil in these engines the mechanic must firmly grasp the pair of upstanding posts with his fingers and turn the oil drain plug counterclockwise to thread the oil drain plug out of the engine.
The oil drain plug is frequently stuck in place and encrusted with oil and dirt, making it difficult to turn. In addition, the oil drain plug is often recessed, exacerbating the problem of its removal. If the engine in question is hot a burn hazard exists. Finally, if the mechanic is of advanced years and possibly suffering from arthritis (as is common among older people), it may be impossible to remove the oil drain plug at all, thereby rendering an oil change impossible. Given that regular oil changes are necessary to achieve maximum engine life, the inability to remove the oil drain plug may lead to premature engine failure.
3. Description of the Prior Art
U.S. Pat. No. 4,794,827 was granted Poling for a Drain Plug Removing Device. This Device is shaped roughly like a thumbscrew and fits over the hexagonal head of an oil drain plug having a hexagonal head. Poling's invention would be unusable on a two post oil drain plug because is is not shaped to grasp a two post oil drain plug. Also, as can be observed in FIGS. 1 and 2, this Device only marginally increases the leverage available to remove a stuck oil drain plug.
Cornia teaches an Apparatus for Manipulating Wingnuts in U.S. Pat. No. 4,357,845. While a standard ratchet socket wrench may be used to turn the apparatus, the use of an appropriately sized socket is required to attach the socket wrench to the Apparatus. In addition, the Apparatus is not shaped to accept a two post oil drain plug, rendering it useless in the removal of two post oil drain plugs.
U.S. Pat. Nos. 4,351,075 and 4,252,037 both teach wrenches capable of engaging the upstanding posts of a two post oil drain plug and rotating same. Neither of these inventions will work if the oil drain plug posts are recessed under the surface of the engine (as occurs fairly frequently). Both these inventions require the purchase of an entire wrench; neither provides an inexpensive adapter that could be used with an existing socket wrench.
Bowers, Jr. et al. describes a Spanner Socket Wrench in U.S. Pat. No. 4,227,429. While this Socket may be used with an existing socket wrench, it is shaped incorrectly to grasp the posts of a two post oil drain plug.
U.S. Pat No. 4,145,939 was issued Garrison for a Drain Plug Holder. This Holder is sized to hold an oil drain plug having a hexagonal head, and does not provide for any means of exerting substantial turning force on the oil drain plug.